Aussie describes Oklahoma tornado terror

Australians living in tornado-ravaged Oklahoma are bracing for more of the killer twisters that have ripped through the US state.

"I've lived here for 30 years and this is unprecedented," Kerry Vincent, the world-renowned, West Australian-born cake designer, told AAP from her home in Tulsa, Oklahoma on Monday.

"My heart bleeds for my friends who I can't find.

"There's so many dead folks, it is just unbelievable."

Ms Vincent said Oklahoma City, hit by a tornado packing 321 km/h winds, is home to some Australians, but she was unaware if they escaped injury.

Phone lines are down and mobile coverage is sketchy.

The terror is not over for locals, with more twisters forecast in coming days.

"We know it's not over," she said.

Ms Vincent, 67, born in Wyalkatchem, WA, is known as the "The Simon Cowell of Cakes" in the US for her acid-tongue while judging US TV cooking competitions and will soon be seen in Australia on the Nine Network's reality cooking show, The Great Australian Bake Off.

She has lived through many tornadoes since marrying her American husband, Doug, and moving to Oklahoma three decades ago.